water can travel great distances inside a building before it drips to make a stain, might help in determining where its coming from. 

When changing carpet after pet damage, odor block any stains with primer.

He have me credits for the normal package they use and I added about $10K for stainless steel, ceiling fans, security fence, stained concreate floors.

I did find a property that is $79k and has many cosmetic issues such as stained wood floors, ugly paint, needs new floorboards, just small things like that.

However, all that is left on interior is cabinets, doors and staining the installed unfinished wood, finish electric / plumbing (installing fixtures etc).

This was the first time I stained a bathroom from tan to white, the process was quick and the price was not bad.

In one of my properties there are plenty of oil stains and cracks in the concrete and I would like to redo it so it looks presentable to tenants again.I've seen some repaint there garage and some do an epoxy coating.

They were the very first tenants to live in the townhouse after we purchased it and did a complete rehab including new wood flooring (destroyed & scratched), new base boards and trim (chewed & scratched by their dog), new granite counters (stained), new appliances (all dinged & scratched), all new light fixtures (electrical not working & light bulbs removed), newer carpet (horribly stained, smells like cat urine when no cat was approved & torn), new paint (holes kicked through in multiple places), doors have holes kicked through, door handle on sliding door ripped off, etc.

Can you just sand and stain it?

Get a long lasting stain and yes reapply as directed.For waterproofing tile or stone is only as good as it’s underlayment makeup.